It is well known that color images are formed by using exposed silver halides as oxidizing agents and reacting oxidized primary aromatic amine-based color developing agents with couplers to produce indophenol, indoaniline, indamine, azomethine, phenoxazine, phenazine and analogous dyes.
Of these, it has been noted that with phenol-based couplers or naphthol-based couplers, which are known as cyan image forming couplers, there are disadvantages such as a reduction in the heat- or light-fastness of the color image formed by color development, or a reduction in the color density occurring when development processing is effected using a bleaching solution (bleach-fixing solution) which has a weak oxidizing power or an exhausted bleaching solution (bleach-fixing solution). In order to improve upon such disadvantages, phenol-based cyan couplers which have a phenylureido group in the 2-position and a carbonamido group in the 5-position have ,.been proposed. These couplers are disclosed, for example, in JP-A-56-65134, JP-A-57-204543, JP-A-57-204544, JP-A-57-204545, JP-A-58-33249 and JP-A-58-33250 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"). These couplers are certainly superior to conventionally known phenol-based cyan couplers and naphthol-based cyan couplers as a result of the abovementioned reasons. But, as noted in JP-A-59-46644, for example, they have disadvantages. For example, the spectral absorption of the colored image varies markedly in accordance with the color density; crystal deposition occurs if sufficiently high-boiling organic solvents are not used on account of their poor solubility; and the color-forming properties are reduced. For these reasons the emulsion film is thick and the sharpness is poor.
On the other hand, naphthol-based cyan couplers having an amido group in the 5-position have been proposed in the laid-open European Patent No. 161626A with a view to reducing the abovementioned reliance of the color density on the spectral absorption of the coupler. As a result of diligent research the present inventors have discovered that the color-forming imperfections and crystal deposition which occur when using, together with small amounts of high-boiling organic solvents, conventional phenol-based cyan couplers having ureido groups in the 2-position which have a high color image fastness and with which there is little color density reduction even with conventional bleaching solutions or bleach-fixing solutions with a weak oxidizing power, do not occur when jointly using these naphthol-based couplers with small amounts of high-boiling organic solvents, and the present inventors have thus made it possible to improve sharpness.
The spread of small-scale retail processing service systems or so-called "mini-labs" in recent years has lead to a strong demand for a reduction in the processing time in order to rapidly meet the customers' processing requirements.
In particular, the strongest demand has been for a reduction in the desilvering stage, which traditionally has occupied the greatest portion of the processing time.
Despite a variety of improvements such as the joint use of bleaching accelerators and the like, there has been a failure to meet this demand because of the basic disadvantage resulting from the weak oxidizing power of ethylenediaminetetraacetic acid iron(III) complex salts which constitute the main bleaching agents used in bleaching solutions and bleach-fixing solutions.
Ferricyanide, dichromates, iron(III) chloride, persulfates, bromates and the like are known as bleaching agents with strong oxidizing potentials. But they have many disadvantages from the point of view of protection of the environment, safety in handling, corrosiveness to metals and the like. As a result, they cannot, presently, be widely used for retail processing or the like.
Given this background, a bleaching solution with a pH of about 6 and containing a (1,3-diaminopropanetetraacetato)iron(III) complex salt as mentioned in JP-A-62-222252 has a greater oxidizing power and is capable of more rapid silver bleaching than bleaching solutions containing ethylenediaminetetraacetic acid iron(III) complex salts. But this bleaching solutions has the disadvantage that color fogging known as "bleached fog" occurs if the bleaching process is carried out directly after color development without the intervention of a bath.
Even disregarding the problem of bleached fog, it has become clear that a new problem, a large increase in staining during the storage of the photosensitive material after processing, will occur if processing is carried out after shortening the bleaching time by using the bleaching solution discussed in the paragraph above.